make code more concise

fishercoder1534 · fishercoder1534 · commit e43ed4833152 · 2016-09-26T21:21:02.000-07:00
diff --git a/EASY/src/easy/ImplementStrStr.java b/EASY/src/easy/ImplementStrStr.java
@@ -3,16 +3,9 @@
 public class ImplementStrStr {
 /**You could use substring as follows, or use two pointers to go through the haystack, if substring API call is not allowed.*/
     public static int strStr(String haystack, String needle) {
-        if(haystack == null || needle == null){
-            return -1;
-        }
-        if(haystack.isEmpty()){
-            return needle.isEmpty() ? 0 : -1;
-        }
-        if(needle.isEmpty()){
-            return 0;
-        }
-        for(int i = 0; i < haystack.length() - needle.length()+1; i++){
+        if(haystack == null || needle == null || haystack.length() < needle.length()) return -1;
+        
+        for(int i = 0; i <= haystack.length() - needle.length(); i++){
             if(haystack.substring(i, i+needle.length()).equals(needle)) return i;
         }
         return -1;
